Let the phone be. Use it normally. If you want that tracker off, here's what you do. Go home straight after school. Greet your mom as you enter the house, head to your room and do your homework. When done, do some advanced reading on your subjects. A few minutes before dinner, go down to the kitchen and help your mom set up the table. Wash the dishes after eating and take out the trash. Stay at home during weekends, tag along with your parents when they go out. Appear interested and enthusiastic with everything they say even if they nag you.
That tracker means your mom doesn't trust you. You simply need to earn it back. Now, if trust isn't that important to you, well you already know there are "other" solutions to your problem but what kind of a person will you become?